Shoe clamping unit



SHOE CLAMPING UNIT Original Filed Nov. 12, 1940 g Sheets-Sheet 1 flaw/WEI Dec. 29, 1942.

K. w. MACDONALD ,788

SHOE CLAMPING UNIT Original Filed Nov. 12, 1940 2 Sheets-Sheet 2 Patented Dec. 29, 1942 SHOE CLAlvlPING UNIT Kenneth W. Macdonald, Watertown, Mass, as signor to Compo Shoe Machinery Corporation, Boston, Mass, a corporation of Delaware Original application November 12, 1940, Serial N 0.

365,320. Divided and this application Decemher 9, 1941, Serial No. 422,247

9 Claims.

This invention relates to a work clamping device and more particularly to a clamping unit for holding aheel in position with a shoe to which the heel is to be attached. A highly satisfactory form of machine for attaching heels to shoes utilizing the clamping unit of the present invention is disclosed in my application for improvements in Heel treating, Serial No. 365,320, filed in the United States Patent Office on November 12, 1940, and of which this present case is a division.

A general object of the invention is to provide an improved heel clamping unit which is simple to construct and which will securely hold a heel in position with a shoe while it is being attached Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements,

and arrangement of parts, which will be exemplified in the construction hereinafter set forth and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in i connection with the accompanying drawings, in which:

Fig. 1 is a side elevation, partly in section, of a heel treating machine embodying features, of the invention;

Fig. 2 is a fragmentary side elevation on an enlarged scale of the heel clamping mechanism shown in Fig. 1;

Fig. 3 is a fragmentary horizontal sectional view taken along line 3-3 of Fig. 2;

Fig. 4 is a fragmentary front elevation along l ne t4 of Fig. 2 and Fig. 5 is a fragmentary view showing a side elevation opposite to that of Fig. 2.

Referring to the drawings, there is shown in Fig. 1 an outline of the machine described in my copending application Serial 'No. 365,320, which comprises a pair of frame castings 28 secured to a suitable base 2| and at their upper ends to a horizontal frame casting 22.

Pivotally mounted in a central vertical bearing 23 cast in the top frame 22 is a hollow ver tical pivot 24 fixed to and rotatable with a clamp post 25. This post has a bottom flange 26 by which it is fixedly screwed to a swinging base 21 recessed on its under side to accommodate a ball; thrust bearing 28 which isinterposed between theswingingclamp base and the upper frame 22. Fixed to the lower end of the pivot 24 is a spring seat and collar 29, the upper surface of which slidably abuts the under face of the frame bearing 23. Thus. the post 25, clamp base 27, post pivot 24, and the collar 28 are fixed together as a unit and may collectively rotate in the frame bearing 23. The post 25 has a bore 38 forming a continuation of the borein hollow post pivot 24, through which a clamp rod 3| is slidably mounted with a suitable key or spline for preventing relative rotation of the rod and post while permitting vertical sliding movement therebetween. A lifting cap 32 is screwed for vertical adjustment into the lower end of rod 3!, and an internally threaded spring seat 33 is adjustably screwed to the lower end of rod 3| above the lifting cap. A strong compression spring 34 is seated between the collar 29 and seat 33 and normally tends to urge the latter and the clamp rod 3| downwardly. This spring applies clamping pressure between the shoe and the heel 35 (shown in clamped position) during the heel treating operation. Attached to the upper end of the clamp rod 3| is a clamp arm 36 held against a shoulder 31 on the rod and by nuts 38 which are threaded to the rod. Abutment of the clamp arm 36 against the upper face of post 25 marks the extreme downward limit of movement of rod 3| under its spring bias. Suitable mechanism hereinafter described is provided for lifting cap 32 against the spring bias and there after permitting it to lower in order to open and close the clamp mechanism to insert or remove work. V

The means for holding the shoe and heel clamped together is best shown in Figs. 2, 3, 4, and 5, and includes a top-lift engaging clamp 40 and a back-heel engaging clamp 4| which are adapted to bear against a heel which is properly positioned by hand on the heel seat portion of a lasted shoe, th last of which is inverted over a short hollow last jack-pin 42 (Fig. 1) which is threaded into the clamp base 21. This base 21 is pocketed at 43 to receive a last supporting block 44 which has a hole allowing it to fit over the last jack-pin 42. In order to insert the shoe and heel' over the jack-pin 42, the clamps 40 and 4| are respectively elevated and retracted by lifting the clamp rod 31. The top-lift clamp 46 is pivoted at 45 to a bar 46 which is press fitted to the lower end of an internally threaded slidable bushing 4'! which is fitted for vertical adjustment within the bore 48 in the forward end of the clamp arm 36. This bushing is adapted to be raised and lowered within its bore by an adjusting screw 49 which is freely rotatable at 50 within the arm 36 and is provided at its upper end with a knob rotation of which causes bushing 41 to raise or lower, thus adjustably determining the height of the top-lift clamp 40 with respect to clamp arm 36 and with respect to back-heel clamp 4| which is on the post 25. The bushing 41 is suitably slidably keyed within the bore 46 to prevent its rotation with respect thereto when the adjusting screw is turned. The angular position of the top-lift clamp 40 can be adjusted for different pitches of heels by means of an adjusting screw 54 which is threaded. through the bar 46 so that its lower end can project therebelow and form a limiting abutment for the pivotally mounted top-lift clamp 43. A tension spring 52 tends normally to hold this clamp against the adjusting screw 54. The adjusting screw is freely slidable within a bore 53 in the arm 36 and a knurled rotating collar 55 is keyed to an elongate keyway 56 in the adjusting screw 54 so that rotation of the collar raises and lowers the adjusting screw with respect to the threaded bar 46. This keyway and the free slidable mounting of the adjusting screw 54 with respect to the arm 36 enables such screw to partake of any vertical adjustments imparted to the bar 46 by its adjusting screw 49.

The back heel engaging clamp 41 is adjustably threaded into the lower end of a rectractable rack 68 which is slidably mounted in a guideway within the clamp post 25. As shown in Fig. 3, this clamp is forked somewhat to engage against the back of a heel and slightly forwardly along the sides of the heel. If wanted, the clamp can be arranged to embrace the heel laterally to any desired extent, and contact between the clamp and heel need not be confined to the back of the latter. The rack 60 is slotted at 6i and a transverse key 62 fixed to the post 25 traverses this slot and prevents rotation and also limits the extent of sliding movement of the rack 60 with respect to the post 25. The toothed portion of the rack 60 meshes with a pinion 63 keyed to a shaft 64 rotatable in the post 25. One end of shaft 64 has a retracting pinion 65 keyed thereto in position to be engaged by a drive rack 66. This is adapted to be lifted by the arm 36 through a bolt 61 which extends through a slot 68 in rack 66 and has a cap or head overlapping such slot and holding the rack slidably against the arm 36 which has a groove to keep the rack in alinement. An adjustable set screw i6 is threaded into the upper end of the rack 66 and projects in slot 68 in position to be engaged and lifted by bolt 61. Elevation of arm 36 accordingly will, after a short interval during which bolt 61 approaches and meets set screw '50, act through rack 6 to rotate shaft 64 and retract the back-heel clamp 41. The latter is normally biased to its downmost projected position by spring means. This comprises a projecting pinion H keyed on the other end of shaft 64 and positioned to be engaged by a projecting rack 12 which is slidably keyed in a spring cylinder 13 on post 25, the lower end of which comprises an adjustably threaded spring seat thimble'l4.

A compression spring 15 seated between this thimble and the rack 12 normally urges the latter outwardly and biases the back-heel clamp 4| downwardly against a heel except during such times as it is retracted by elevation of the clamp arm 36. Thus, when a shoe and heel are set over last jack-pin 42 and clamp rod 3| is permitted to descend under its spring bias, the heel is held firmly against the inverted shoe by engagement of the top-lift clamp and back-heel clamp therewith, the pressure exerted by spring 34 being transmitted through the top-lift clamp to the lasted shoe, and in turn to the last supporting block 44 and clamp base 21. By virtue of the loose motion of bolt 61 in slot 68, the back-heel clamp 41 can yield against spring 15 when it strikes the heel, accommodating itself to a proper position with respect to the top-lift clamp for any given style of heel, and bearing against the heel with the force exerted by spring I5, which is pre-loaded to a suitable extent. The top-lift clamp 40 is vertically adjusted to engage the heel shortly after clamp 4| during descent of arm 46, to assure proper contact of clamp M with the rear of the heel. The arrangement also provides for retraction of the top-lift and backheel clamps in unison during the latter portion of the top-lift clamp raising or opening movement, while providing independent spring pressure of these clamp parts under their respective spring biases 34 and 15 during the latter portion of the lowering or closing movement of the toplift clamp. All of these parts including the clamped shoe and heel are rotatable with respect to the main frame as the unit pivots in the bore 23 in the upper frame casting 22, and thus the entire clamping unit and shoe can be swung into alinement with different tools used during heel treating operations.

One suitable means for raising the clamp rod 3i against its spring bias may comprise a motor driven hydraulic thrustor which is so arranged that as long as its motor is energized and operating, fluid pressure is applied against a piston so as to project and hold projected its thrust rod 8| (Fig. 1). Upon stopping of the motor, the thrust rod settles back to its initial position. The vertical travel of the rod is confined between definite limits. Such motor driven hydraulic thrustors are commercially available in various types and their details need not be explained here. In the present machine the thrust rod 8| is, upon actuation of the thrustor motor, adapted to be forced upwardly against a roller 82 carried at the end of a lever 83 keyed to a rock shaft 84 mounted in the upstanding frame members 26. Lever 83 carries a roller 85 adapted to engage and lift cap 32 on the lower end of clamp rod 3|.

A suitable foot operated switch may be provided for controlling the thrustor motor, thus leaving the operators hands free for inserting work into the clamp which may be raised or lowered at will.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a heel treating machine, a clamping unit comprising a shoe support, a top-lift clamp opposite said support, a back-heel clamp, means for moving said top-lift clamp toward and from said support, spring means urging said backheel clamp to heel engaging position, and means including a loose motion connection between said back-heel clamp and said first mentioned means arranged to enable said back heel clamp to partake of the retracting movement of said toplift clamp and to project into holding engagement with a heel under its own spring bias only.

2. In a heel treating machine, a clamping unit comprising a shoe support, a top-lift clamp, a back-heel clamp, means for moving said toplift clamp toward and from said support to clamp a shoe and heel therebetween, spring means urging said back heel clamp against a heel held between said top-lift clamp and shoe support, and retracting means for said back-heel clamp coupled with said first mentioned means arranged to retract said back-heel clamp shortly after said top-lift clamp is moved away from said support and to permit the back-heel clamp to engage and hold against a heel member under its own spring bias when said top-lift clamp is moved toward said support.

3. In a heel treating machine, a clamping unit comprising a shoe support, a top-lift clamp, a back heel clamp, independent spring means respectively associated with said clamps for urging them into closed position against the heel of a shoe held on said support, means for retracting said top-lift clamp, and means including a loose motion connection between the said back heel clamp and said retracting means enabling said clamps to be retracted in unison and to bear against said heel independently.

4. In a heel treating machine, a clamping unit comprising a base carrying a shoe support and a relatively fixed upstanding post, a top-lift clamp overhanging said support slidably mounted on said post, a back-heel engaging clamp slidably mounted on said post, a spring urging said back-heel clamp toward the heel of a shoe on said support, means for raising and lowering said top-lift clamp, and means including a loose motion connection between said backheel clamp and said last raising and lowering means for retracting said back-heel clamp during the latter stages of the raising movement of the top-lift clamp.

5. In a heel treating machine, a clamping unit comprising a base carrying a shoe support and a relatively fixed upstanding post, a top-lift clamp overhanging said support, means for moving said clamp toward and from said support, a rack slidable on said post and carrying a back-heel engaging clamp, a rack carried with said means, and pinion means rotatable on said relatively fixed post meshing with said racks and arranged to impart opening movement to said back-heel clamp during the opening movement of said toplift clamp.

6. In a heel treating machine, a clamping unit comprising a base carrying a shoe support and an upstanding post relatively fixed with respect to said base, a top-lift clamp overhanging said support, means for moving said clamp toward and from said support, a rack slidable on said post and carrying a back-heel engaging clamp, a second rack having a loose motion connection with said means arranged to partake of a portion only of the opening and closing movements of said top-lift clamp, and pinion means rotatable on said relatively fixed post meshing with said racks arranged to impart common opening and closing movement to said clamps, said loose motion connection being arranged to permit independent relative movement of said clamps during the final portion of the closing movement thereof.

7. In a heel treating machine, a clamping unit comprising a base carrying a shoe support and an upstanding post relatively fixed with respect to said base, a top-lift clamp overhanging said support, means for moving said clamp toward and from said support, a rack slidable on said post and carrying a back-heel engaging clamp, a rack carried with said means, pinion means rotatable on said post meshing with said named racks arranged to impart opening movement to said back-heel clamp, a third rack slidable on said post and meshing with said pinion means, and spring means urging said third rack in a direction to rotate said pinion means so as to impart closing movement to said back-heel clamp.

8. In a heel treating machine, a clamping unit comprising a base carrying a shoe support, a toplift clamp opposite said base, a back-heel engaging clamp, and common means for retracting both of said clamps, said means including a loose motion connection to said back-heel clamp for delaying the retraction of same until partial retraction of said top-lift clamp has taken place.

9. In a heel treating machine, a clamping unit comprising a base carrying a shoe support, a top-lift clamp opposite said base, a back-heel engaging clamp, spring means for urging said back-heel clamp toward closed position, and common means for retracting both of said clamps, said last mentioned means including a loose motion connection to said back-heel clamp for delaying the retraction of same until partial retraction of said top-lift clamp has taken place.

KENNETH W. MACDONALD. 

